Universal caster assembly for leg supported stands



June'Z, 1959 E. c. wARRlcK ETAL 2,888,707

UNIVERSAL CASTER ASSEMBLY FOR LEG SUPPORTED STANDS Filed June 2, 1954 2 Sheets-Sheet 1 S w ,Ww Tx v/N y@ wm ff D R P Mm y 6J.

E. c. wARRlcK ETAL 2,888,707

June 2, 19,59

UNIVERSAL cAsTER ASSEMBLY FOR LEG sUPPoRTED STANDS Filed June 2, 41954 2 Sheets-Sheet 2 INVENTORS bw/mo 6.' Mnl/cx JasIP/l Mrrz ATIORNEES' CASTER ASSElVIBLY FOR LEG SUPPOR'IED STANDS Edward c. Warrick, Piusburgnand Joseph Kmetz, Ram

kin, Pa., assignors to Rockwell Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application June 2, 1954, Serial No. 434,011 3 claims. (Cl. 1633) This invention relates to caster assemblies and more particularly to retractable caster wheel assemblies for use on power tool stands and the like to facilitate movement thereof from place to place. I

The limited work space available in many home and other workshops often requires that power tools such as bench saws and the .like used in the shop |be moved back out vof the work area into a storage space when the work with the tool has been completed to clear the shop working .area for use of other tools or for other purposes. The combined weight of the power tool and its 'stand is such that movement is difficult unless the stand is provided with suitable roller means. Conventional casters can not satisfactorily be used because, even if .the locking type, they do not provide adequately rm -footing for. the tool stand during operation of the power tool'carried thereby.

It, accordingly, is the purpose of the present invention to providepower tool stand caster assemblies which facilitate movement of the stand and tool from place to place and yet permit a rmset up of the stand duling operation of the-tool mounted thereon.

In accordance with the invention, power tool stands are provided with casters adapted to be moved vertically relative to the stand legs into or out of engagement with the oor, to thereby lift the stand from the-floor and onto the casters for movement of the stand and to lower the stand so that is feet rest rmly on the oor for operation'of the power tool.

Itis another object of this invention to provide new and improved retractable caster assemblies for use on power tool stands and the like characterized by simplicity of 'structure and operation, ruggedness and economy of manufacture. l

-A further object of this invention is the .provision of novel retractable caster assemblies wherein the casters may be conveniently and easily moved between inoperative` and operative positions and rmly locked in the latter position.

-lt is also an object of `this invention to provide new and'improvedretractable caster assemblies adapted to be quickly and easily attached to existing power tool and like stands of different widths and lengths.

Another object of this inventionl is the provision of novel cam elements ffor use in the retractable caster assemblies of our invention.

These and other objects, features and advantages of the' invention will become more fully apparent by reference' to the appendedclaims and the following detailed descriptionwhen read in conjunction with the accompanying drawings, wherein:

Figure l -is a front elevation of a power tool stand equipped with the retractable caster assemblies of our invention; l

Figure 2 is a horizontal sectional View taken on the line 2--2 of Figure l and showing the caster assembliesin Plan;v

Figure 3 is a sectional view taken on the line 3;;3

of Figure 2 and showing one of the caster support units with the caster in both retracted and extended positions;

Figure 4 is a Ifront elevation of a castersupport unit as viewed in the direction indicated by arrows 4-4 in Figure 2 and omitting the associated stand leg; and

Figure 5 is a plan view of a pair of cam elements,

and illustrates their method of manufacture. l.

With continued reference to the drawings, wherein like reference numerals are used throughout to designate-. like parts, Figure l shows a power tool stand 10 of conventional type equipped with the retractable caster as semblies 11 of our invention. Power tool stand 10 includes a at table surface 12 supported on legs 14 and adapted to mount a power tooll and its motor or other devices (not shown). The legs surface and between the stand legs. Y As best shown in.

Figure 2, stand legs 14 are formedof L-'sectionangle iron or the like and are curved outwardly .and flattened'v adjacent their lower ends to formY outwardly disposed sup port feet 1S.

The retractable caster assemblies 1 1 of this invention.v fit within the space between the stand legs and'include.v

foot treadles 20 located exteriorly of thelegs in a position such that they may 'easily bemanipulateid the foot of the operator to selectively retract'ori-extend:

the associated casters 22 and 24. In Figure'fl the casters are shown retracted and the `treadles 20 in the positions which they occupy when the casters are retracted. Ro-

tation of treadles 20 in aV counterclockwise directior r (Figure l) will force casters 22 and 24 downwardly and thus lift the stand onto t-he casters in a mannerwhich will be more fully described hereinafter. Means4 areH provided `to automatically lock the casters in vslklpporting 1 j position to permit movement of the stand without dangerv of the casters retracting and permitting the .standjfeetvto drop to the oor. After the stand Yhas been moved` to the desired position the foot treadles may' be rotated in the reverse (clockwise) direction to retract t-he casters. and permit the stand feet to lower and against rest inY supporting position on the floor, to thus provide a firm.v footing for the stand during operation ,of the power toolv carried thereby.

As shown in Figure lar structure but reversed from left to right so that each is the mirror image of the other.v Thus, thek support blocks at the stand legs diagonally opposite each other are identical and interchangeable, while those at the legs. directly opposite each' other are similar but of opposite;

The structure rof each Yof these support blocksis best-1 Patented June,2, ,195 9 2, wherein the castersV have been omitted for purposes of clarity, the caster retraction and extension mechanism of our invention consists o f `a pair i of caster assemblies 26, one for each side ,of the stand,l each assembly being tted to one pair of the ltool stand legs 14. Each caster assembly consists of an actuating shaft 28 extending between and journaled in ,apair of.` caster support blocks 30 and 32. One end of each sha-iti 28 extends beyond the adjacent caster support'blockand carries on its lextended end one of the foot treadles. 20,' ixedrthereto as by a pin 34 or the like. The supportblocks 30 and 32 of each caster assembly 26 are of simi-g shown Figures 3 and 4, the associated tool stand leg being omitted from the latter figure for purposes of clarity. Support block 32 comprises a support frame indicatedgenerally at 36 and made up of a base portion 318,.,Shank portion40 and caster stem journal portion 42. i The base portion 38 of support frame 36 underlies the foot 18 of the associated stand leg and is secured thereto 21S, by `'c1 stud44 extending through aligned bores in foot 1 8 and base 38 and provided with a nut 4S adapted to be turned `down on the stud to clamp the foot and base firmly together. Base portion 38 may be relieved as shown at 47 (Figures 2 and 3) so that when the stud and bolt are tightened base 38 will tend to pivot about the point of engagement of its non-relieved portion 48 with the flat undersurface of foot 18, and thus urge the shank portion 40 of support frame 36 more rmly into engagement with the inner side of the associated tool stand legl 14. Shank 40 is preferably made of angle section and curvature corresponding to the inner surface `of'lgegll` so as to interlit snugly therewith when thesupport frame is secured to the leg.

Alternatively, the under-surfaces of the stand feet 18 maybe relieved at the outer edges thereof which overlie the non-relieved portions of the support frame base porti'ons 38, this arrangement being illustrated at the lefthaud' sidepof the stand shown in Figure 1. With this ar.- rangement, the stand feet and support frames have interengaging abutment surfaces as at 49 in Figure l, which serve to properly position the support frames 36 with respect to feet 18 and to reduce shearing stresses on studs 44. These (stresses arisefrom the upward pull on shank shank`portions'40 to urge these elements rmly into engagement with the inner sides of the table legs.

Support frame 36 includes a caster stem journal portion 42 formed integrally with the upper end of shank portion 40' and extending inwardly with respect to the associated stand leg 14. 'I'he caster stem journal con- .'sistsoffthree generally vertically extending wall members 50, 52, and 54, and a bottom wall member. 56 having adownwardly extending circular boss or projection 58; the several wall members preferably being integrally formed with shank portion 40 of the support frame. Vertical walls 52 and 54, as best shown in Figure 4,1 define an upwardly divergent recess and Iare provided withY aligned horizontal bores 60 and 61 therethrough journalling an end portion of shaft 28. Bottom wall 56 and itsintegral boss or projection 58 are'provided with a vertical bore 63 therethrough centered on the axis of bores 60A-'and 61. BoreY 63-slidably'androtatably receives-thestem 65-of a caster wheel `24-of conventional type.` The upper endof stem 65 protrudes into the recess betweenthe Vertical walls 52 and 54.` This recessabove' theend-of casterl stem 65' receives a camelement 67 which is secured to shaft 28 as by a pin 69 passing;

through the shaft andr cam or by other convenient fasten-- ing means. y Rotation of the shaft-and cam elementiis properlyv centeredk between them.

Asbest shown in Figure 3, the camming surface of cam cam- 67 .in respective retracted position and `the phantom linesshowthecaster and Vcam in extended position.` The corresponding positionsk of treadle 20-and`cams67- aretsmilarlyjshownin Figure .3; As ,isvapparentffrorn this ligure, the camming surface of cam 67-engages the stem: end-` rof 4:caster 24 nto. causeedownward @1 jacking movement ofthe caster upon rotation of the cam in a clockwise direction. The caster stem engages the circularly curved portion 71 of the camming surface when in the retracted position shown in full lines and until the caster reaches its fully extended position at which time the planar portion 73 is brought into contact with the caster stem end as shown in phantom lines in Figure 3. The shape of the camming surface of 'the is such that when the cam' is rotated into this latter position it is held against any accidental reverse rotation whichy would retract the caster and lower the stand. Y

In order for the cam to turn back and permit the caster to retract it is first necessary that it' further raise the tool stand suiciently to permit the caster stem to ride over the line of juncture ofthe planar and circularly curved cam surfaces. The weight of the stand and the tool carried thereby thus assists in preventingY retraction of the casters until such time as it is desired 'to retract them. Retractionmay then be accomplished by exerting sufficient foot pressure on treadl'es- 20 'in acounterclockwise direction' to rotate the cams and raise:V the stand slightly so that caster stems 62 can ride over the high points on the camming surfaces and thereafter counterbalancing the weight ofthe stand acting throughcaster stems 65 to slowly turn cams 67 into the positionI shown insolid lines in Figure 3V thereby slowly ldweringy the standfeet until they are resting ony the oor and the casters are carrying. none of the weight of the standar The height to which the stand feet are elevated-by extension of thefcasters is determined both by the con-2 figuration of the cams 67; andbythe length'of` the'caster stems 65. With cams of given shape and size suchfforexample,v as shown inFigure 3, itv ispossible 'to-varythe range of caster movement and thus o fv stand-elevation-- by making thecaster stems either longer 'or slightly shorter than those shown. The caster stems shouldnot beso short that the stand feet fail to clear the door Whenthe casters are extended by. rotation ofcams 67 into-the position shown in phantom linesin Figure3, nor shouldw they be so long that the stand feet do not rest rmly on-the iloor when the casters are retracted .by rotation ofcams 67 into the position at whichtheir camming surfaces permit maximum rise of the caster stemsywhich. camposition is=about30LV1 counterclockwise ofthat illustrated in solid lines in Figure 3. Between these limits, the length of the caster stems may be Variedtomodify' the range of vertical movement of the casters, and, accordingly, of the stand feet. The amount of clearance between the stand feet and `floor when the casters are in their extended position may thus be adjusted tobestl suit particular applications and floor conditions. Y

As shown in Figure 2, the two caster support units 30 and 32Y ofeach pair are interconnected into a unitary t assemblyby the Vassociatedshaft 28 journaled in the units and held therein -by the cams 67 fixed on the shaft.` Each of the shafts 28 may if desiredbe providedon .its` end opposite the foot treadle with a plurality of axially spaced additional bores adapting .the caster support assemblies to use on power tool stands of diierent sizes. Thus, if it is desired to fit the caster assemblies to a'A smaller stand, the support units thereof opposite treadles 20 are moved further onto the shaft and lixedin suchy inward position by placing the cam pin 69'int`o the appropriate one ofthese additional shaft bores 80.

It is to be noted that the caster support assembliesf. maybe mounted on the tool stand with thefoot treadle's".v positioned at either side or, if desired, at the front or? rear of the stand, whichever is more convenient for the operator. It also is possible toV arrange .tlietwoi'footl4 treadles so that when thecasters controlledl 'therebyae in=like` positions the treadl'es will either-beparallel-tof each other as shown in Figure l or be oppositely inciiiilP and rotatable in-opposite directions to" raise or lower the casters; Where the treadles are arranged parallel as 'in- Figure 1 the cams 67 on the two shafts ZSfiwill-tli e .f am elements 83 and 8.4;

assai@ treadles-Z, on the'A shafts 28of' 'theright' and left-hand easter assemblies, the two treadles may bei made either para-llelvand rotatable in the s ame direction orv oppositely inclinedandrotatable-in oppos'itedirectiis' to raise orlower thexlcast'ers; j

Wejhav'e found that cams of thetype showni'inV-Figure 'ay cnyenie'ntly' be' fabricated inthe 'if illusappropriate thickness` and' of a' diameter such' as to proa Qirulrlv Curved c'a'riiiinjg" Surface 9i'. 'sjired ra. u's'fof curvature; aminor segmentjaof the discfvindicated by'A ldotted' lines`"is savved or otherwise :cut therefrom along a` chord line 82 of the disc. disc is the enf e by sawingV along thediajnieter s1' di] eef endi arterthechrd 82; to thus form twdidentie'al The elements'may then beL drilled to providebores Sti-for the shafts' on which they are to be mounted and bores: S'S'for the locking pins ,far fixing them to the Shaft-S- .Thelins f inname between theA circulafrly curvedY surface 71 and planar surface 75 may if desired be slightly' rounded, as indicated ,at 9,0' in' Figure, 5; to permit4 easienmoveine'nt of the caster stem which engages these surfaces front onef surface to the other upon rotation of the cam.

Instead of starting with a disc as described above, it also is possible to produce the cams from a relatively long rod of circular cross section. The rod is rst cut lengthwise tot remove a minor segment of the circular cross section thereof, then may be drilled lengthwise of the rod to provide the two shaft bores 86. The rod is next cut along its diameter normal to the chord along which said segment was removed, and the junction between camming surfaces 71 and 73 rounded as by grinding or other machine operation. The two rod portions thus forme@ may then be cut transversely of their lengths into, ca m elements of the desired width, and the cam elements drilled to Provide the bores 88 for the shaft pins.A r[he sequence in which these steps are carried out may be varied, if desired, tot better suit particular conditions and available metal working machines.

From the foregoing it will be apparent that we have developed new, novel and highly advantageous retractable c aster assemblies for-use on; power toolA stands andthe like. While the retractable caster assemblies of our i11- vention have been described with particular reference to power tool stands, it is to be understood that these caster assemblies are not restricted to use' on such stands but may equally well be used on stands, tables and supports of other types, wherever there is a need for retractable casters.

The invention may be embodied in other specific forms without departing from; the spirit or essential characteristics thereof. The present embodiments. are therefore to be considered in, all respects as illustrative and not restrictive, the scope of the; invention being indicated by the appended claims rather than by the. foregoing descrip tion, and all. changes which come within the meaning and range of equivalency of the claims are. therefore intended to be embraced therein.

What we claim and wish to protect by United States Letters Patent is:

1. As an article of manufacture, a retractable caster assembly comprising a pair of spaced apart support blocks having a oor engaging base, a journal portion formed integrally near the upper end of each support block and having divergent opposed walls to form a divergently opposed walled recess, each of said journal portions defining a vertical bore extending therethrough and centered between the divergent opposed walls to intersett'saidY di- ,6 vergently walledV recess, said divergent opposed walls 'having-horizontally aligned" bore'si''iiit'rsectii1-` l 51a caster stenti jo'nalldiiiv each ofsaid erticalibo're b for reciprocal noierrlent therein and hav g anfuppn extending into` its respective recess?, a caster oa each of said stems on" the lower end th ""o`f a rotatable shaft extending@ betwe'enfsai blocks alignedboies tbe' journalldlin sai'dh br'esmeans' for rotating saidl shaft, al amelemen verticallystaiidihgparallel sides'andnonrotatably ed; o'n the portions of saidshaftf lyingin calchi-of theyrespe'ctive recesses for operative c ngfagemeritk wit saidl per" end of a; respective caster stem, the edges fo by the periphery of each` of said cam elements and" itsparallel' sides* beingv disposed' to'- make' line"c'oii'tt" v'vithl rspective ones of said` divergent'v opposedvval'ls to axialv movement ofy saidA shaft thereby maintain cam' elements alignedv with'l their respectlv'ela' caster stems and in' fictioriah contact' with said walls at alltirnes` te permit lsiibsltanii l'y fieefrett said shaftand': saidV cams in opl n 2^. As'- an' article of manufactur assembly comprising a2 pair of `sp` blocks cach' having a floor enga angle iron shank portion extend i g upw e e e base portion, a web-like,l horizo'tally' d ls seclfnj,A portion formed integrally with saidV portion and extending adjacent the' lippen 'endx thereofV4 and: d Y ng upstanding substantially" right angl'arly intersecting w Ills at one side and one end of said journal portion, said walls along said sides having divergent opposed faces and horizontally disposed journal bores, a boss-like socket member extending downwardly from each of said web portions and defining a vertical bore extending therethrough, the axis of each of said vertical bores being disposed to intersect with the axis of said horizontally disposed journal bore; a caster stem journalled in the vertical bore of each support block for reciprocal movement therein and having an upper end projecting beyond respective ones of said web-Ike journal portions; a caster carried by each of said stems on the lower end thereof; a rotatable shaft extending between said blocks and through said horizontally disposed journal bores to join said pair of support blocks in assembled relation with their respective divergent wall faces in relative opposed relation with said shaft journalled in said horizontally disposed journal' bores; means for rotating said shaft; a cam element hav ing vertically standing parallel side faces mounted on the portions of said shaft substantially overlying said caster stems for operative engagement with said upper end of a respective stem, at least one edge of each of said cani elements formed by the periphery of said cam element and an intersecting parallel side face being disposed to make line contact with the respective adjacent divergent wall face to thereby limit axial movement of said shaft in opposite directions to maintain said cam elements vertically aligned with its respective caster stems and in minimal frictional contact with said upstanding divergent wall faces at all times to permit substantially free rotation of said shaft and said cam elements in cooperation of said assembly. y

3. A retractable caster unit for use on a leg stand support provided with lower angle iron end portions, comprising: a pair of spaced apart caster support blocks each having a oor engaging base portion adapted to be attached to one of said lower end portions of said leg stand support; an angle iron shank portion comprising two outwardly facing intersecting Walls extending upwardly from each of said base portions and adapted to snugly interlit and abuttingly engage with the underside of respective ones of said lower angle iron end portions of said leg stand support substantially along the entire sur-y 'each of said web portions to deiine a substantially ver-` tical bore extending therethrough, the axis of said verticalbore intersecting the axis of said horizontal bore .above said web-like wall portion, a caster stern journalled in each of said vertical bores for reciprocal movement therein having an upper end extending above said web portion; a caster carried by each of said caster stems on thel outer end thereof; a rotatable shaft extending between said support blocks and journalled in each ofsaid 'horizontally disposed journal bores of respective ones of said support blocks to join said pair of support blocks in assembled relation with their respective divergent wall faces in relative opposed relation with said shaft', a cam element having vertically standing parallel side faces mounted on each portion of said shaft overlying said vertical bores for operative engagement with the upper .j l

end of a respective caster stem, the outer edge of each of said cam elements formed by the periphery of said cam element and outer intersecting side face thereof being disposed to make line contact with respect adjacent di- Ianuary 1953.

vvergent wall faces to thereby limit'axial movement of said shaft inopposite directions; to maintain said cam elements vertically aligned with its'respective casterstem vand in minimal frictional contact with said .upstanding divergent wall faces at all times topermit substantially face rotation of said shaft and said cam elements in operation of said unit, y References Cited in the le of this patent UNITED STATES PATENTS y 280,273 wilson June 26, 1882i 329,586 Montres Nov. -3, 1885 443,260 Preston Dec. 23, 1890 654,776 l Barber Julyl, 1900 940,606 Medart Nov. 16, 1909 940,749 Sweet Nov. 23,1909 1,092,220 Koch et al. Apr. 7, '1914 2,343,253 Clark Mar. 7, 1944 A 2,490,953 Eriksen Dec. 13, 1949 2,671,242 Y Lewis Mar. 9, 19,54 2,735,130; Unsworth Feb. 2l, 1956 -FOREIGN PATENTS t 1,640 Great Britain of 1871 p OTHER REFERENCES i ,Y Retractable'Caster, page 217 of Popular Mechanics, 

